1 //===----- lib/Support/Error.cpp - Error and associated utilities ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Support/Error.h"
10 #include "llvm/ADT/Twine.h"
11 #include "llvm/Support/ErrorHandling.h"
12 #include "llvm/Support/ManagedStatic.h"
13 #include <system_error>
14 
15 using namespace llvm;
16 
17 namespace {
18 
19   enum class ErrorErrorCode : int {
20     MultipleErrors = 1,
21     FileError,
22     InconvertibleError
23   };
24 
25   // FIXME: This class is only here to support the transition to llvm::Error. It
26   // will be removed once this transition is complete. Clients should prefer to
27   // deal with the Error value directly, rather than converting to error_code.
28   class ErrorErrorCategory : public std::error_category {
29   public:
30     const char *name() const noexcept override { return "Error"; }
31 
32     std::string message(int condition) const override {
33       switch (static_cast<ErrorErrorCode>(condition)) {
34       case ErrorErrorCode::MultipleErrors:
35         return "Multiple errors";
36       case ErrorErrorCode::InconvertibleError:
37         return "Inconvertible error value. An error has occurred that could "
38                "not be converted to a known std::error_code. Please file a "
39                "bug.";
40       case ErrorErrorCode::FileError:
41           return "A file error occurred.";
42       }
43       llvm_unreachable("Unhandled error code");
44     }
45   };
46 
47 }
48 
49 static ManagedStatic<ErrorErrorCategory> ErrorErrorCat;
50 
51 namespace llvm {
52 
53 void ErrorInfoBase::anchor() {}
54 char ErrorInfoBase::ID = 0;
55 char ErrorList::ID = 0;
56 void ECError::anchor() {}
57 char ECError::ID = 0;
58 char StringError::ID = 0;
59 char FileError::ID = 0;
60 
61 void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner) {
62   if (!E)
63     return;
64   OS << ErrorBanner;
65   handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
66     EI.log(OS);
67     OS << "\n";
68   });
69 }
70 
71 
72 std::error_code ErrorList::convertToErrorCode() const {
73   return std::error_code(static_cast<int>(ErrorErrorCode::MultipleErrors),
74                          *ErrorErrorCat);
75 }
76 
77 std::error_code inconvertibleErrorCode() {
78   return std::error_code(static_cast<int>(ErrorErrorCode::InconvertibleError),
79                          *ErrorErrorCat);
80 }
81 
82 std::error_code FileError::convertToErrorCode() const {
83   std::error_code NestedEC = Err->convertToErrorCode();
84   if (NestedEC == inconvertibleErrorCode())
85     return std::error_code(static_cast<int>(ErrorErrorCode::FileError),
86                            *ErrorErrorCat);
87   return NestedEC;
88 }
89 
90 Error errorCodeToError(std::error_code EC) {
91   if (!EC)
92     return Error::success();
93   return Error(std::make_unique<ECError>(ECError(EC)));
94 }
95 
96 std::error_code errorToErrorCode(Error Err) {
97   std::error_code EC;
98   handleAllErrors(std::move(Err), [&](const ErrorInfoBase &EI) {
99     EC = EI.convertToErrorCode();
100   });
101   if (EC == inconvertibleErrorCode())
102     report_fatal_error(Twine(EC.message()));
103   return EC;
104 }
105 
106 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
107 void Error::fatalUncheckedError() const {
108   dbgs() << "Program aborted due to an unhandled Error:\n";
109   if (getPtr()) {
110     getPtr()->log(dbgs());
111     dbgs() << "\n";
112   }else
113     dbgs() << "Error value was Success. (Note: Success values must still be "
114               "checked prior to being destroyed).\n";
115   abort();
116 }
117 #endif
118 
119 StringError::StringError(std::error_code EC, const Twine &S)
120     : Msg(S.str()), EC(EC) {}
121 
122 StringError::StringError(const Twine &S, std::error_code EC)
123     : Msg(S.str()), EC(EC), PrintMsgOnly(true) {}
124 
125 void StringError::log(raw_ostream &OS) const {
126   if (PrintMsgOnly) {
127     OS << Msg;
128   } else {
129     OS << EC.message();
130     if (!Msg.empty())
131       OS << (" " + Msg);
132   }
133 }
134 
135 std::error_code StringError::convertToErrorCode() const {
136   return EC;
137 }
138 
139 Error createStringError(std::error_code EC, char const *Msg) {
140   return make_error<StringError>(Msg, EC);
141 }
142 
143 void report_fatal_error(Error Err, bool GenCrashDiag) {
144   assert(Err && "report_fatal_error called with success value");
145   std::string ErrMsg;
146   {
147     raw_string_ostream ErrStream(ErrMsg);
148     logAllUnhandledErrors(std::move(Err), ErrStream);
149   }
150   report_fatal_error(Twine(ErrMsg));
151 }
152 
153 } // end namespace llvm
154 
155 LLVMErrorTypeId LLVMGetErrorTypeId(LLVMErrorRef Err) {
156   return reinterpret_cast<ErrorInfoBase *>(Err)->dynamicClassID();
157 }
158 
159 void LLVMConsumeError(LLVMErrorRef Err) { consumeError(unwrap(Err)); }
160 
161 char *LLVMGetErrorMessage(LLVMErrorRef Err) {
162   std::string Tmp = toString(unwrap(Err));
163   char *ErrMsg = new char[Tmp.size() + 1];
164   memcpy(ErrMsg, Tmp.data(), Tmp.size());
165   ErrMsg[Tmp.size()] = '\0';
166   return ErrMsg;
167 }
168 
169 void LLVMDisposeErrorMessage(char *ErrMsg) { delete[] ErrMsg; }
170 
171 LLVMErrorTypeId LLVMGetStringErrorTypeId() {
172   return reinterpret_cast<void *>(&StringError::ID);
173 }
174 
175 LLVMErrorRef LLVMCreateStringError(const char *ErrMsg) {
176   return wrap(make_error<StringError>(ErrMsg, inconvertibleErrorCode()));
177 }
178